Nozzle assembly for supporting slide movement of a valve assembly

ABSTRACT

A mold-tool system ( 100 ) configured to accommodate a valve stem ( 104 ), the mold-tool system ( 100 ) comprising: a nozzle assembly ( 402 ) having: a nozzle-output end ( 408 ) being configured to support, at least in part, slide movement of the valve stem ( 104 ).

CROSS-REFERENCE TO RELATED PATENT APPLICATION(S)

This patent application is a continuation-in-part patent application ofprior U.S. patent application Ser. No. 13/144,945, filed 18 Jul. 2011.This patent application also claims the benefit and priority date ofprior PCT Application No. PCT/US2011/039,533, filed 8 Jun. 2011, whichclaims priority from prior U.S. Patent Application No. 61/353,673, filed11 Jun. 2010.

TECHNICAL FIELD

An aspect of the present invention generally relates to (but is notlimited to) a mold-tool system.

BACKGROUND

The first man-made plastic was invented in Britain in 1851 by AlexanderPARKES. He publicly demonstrated it at the 1862 International Exhibitionin London, calling the material Parkesine. Derived from cellulose,Parkesine could be heated, molded, and retain its shape when cooled. Itwas, however, expensive to produce, prone to cracking, and highlyflammable. In 1868, American inventor John Wesley HYATT developed aplastic material he named Celluloid, improving on PARKES' invention sothat it could be processed into finished form. HYATT patented the firstinjection molding machine in 1872. It worked like a large hypodermicneedle, using a plunger to inject plastic through a heated cylinder intoa mold. The industry expanded rapidly in the 1940s because World War IIcreated a huge demand for inexpensive, mass-produced products. In 1946,American inventor James Watson HENDRY built the first screw injectionmachine. This machine also allowed material to be mixed beforeinjection, so that colored or recycled plastic could be added to virginmaterial and mixed thoroughly before being injected. In the 1970s,HENDRY went on to develop the first gas-assisted injection moldingprocess. Injection molding machines consist of a material hopper, aninjection ram or screw-type plunger, and a heating unit. They are alsoknown as presses, they hold the molds in which the components areshaped. Presses are rated by tonnage, which expresses the amount ofclamping force that the machine can exert. This force keeps the moldclosed during the injection process. Tonnage can vary from less thanfive tons to 6000 tons, with the higher figures used in comparativelyfew manufacturing operations. The total clamp force needed is determinedby the projected area of the part being molded. This projected area ismultiplied by a clamp force of from two to eight tons for each squareinch of the projected areas. As a rule of thumb, four or five tons persquare inch can be used for most products. If the plastic material isvery stiff, it will require more injection pressure to fill the mold,thus more clamp tonnage to hold the mold closed. The required force canalso be determined by the material used and the size of the part, largerparts require higher clamping force. With Injection Molding, granularplastic is fed by gravity from a hopper into a heated barrel. As thegranules are slowly moved forward by a screw-type plunger, the plasticis forced into a heated chamber, where it is melted. As the plungeradvances, the melted plastic is forced through a nozzle that restsagainst the mold, allowing it to enter the mold cavity through a gateand runner system. The mold remains cold so the plastic solidifiesalmost as soon as the mold is filled. Mold assembly or die are termsused to describe the tooling used to produce plastic parts in molding.The mold assembly is used in mass production where thousands of partsare produced. Molds are typically constructed from hardened steel, etc.Hot-runner systems are used in molding systems, along with moldassemblies, for the manufacture of plastic articles. Usually,hot-runners systems and mold assemblies are treated as tools that may besold and supplied separately from molding systems.

SUMMARY

The inventors have researched a problem associated with known moldingsystems that inadvertently manufacture bad-quality molded articles orparts. After much study, the inventors believe they have arrived at anunderstanding of the problem and its solution, which are stated below,and the inventors believe this understanding is not known to the public.

Generally, known valve stems bend and deflect in a hot runner nozzle,which may inadvertently accelerate wear of a nozzle tip and a gateinsert.

According to one aspect, there is provided a mold-tool system (100)configured to accommodate a valve assembly (104), the mold-tool system(100) comprising: a nozzle assembly (402) having: a nozzle-output end(408) being configured to support, at least in part, slide movement ofthe valve assembly (104).

According to another aspect, there is provided a molding system havingthe mold-tool system (100) described above.

Other aspects and features of the non-limiting embodiments will nowbecome apparent to those skilled in the art upon review of the followingdetailed description of the non-limiting embodiments with theaccompanying drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

The non-limiting embodiments will be more fully appreciated by referenceto the following detailed description of the non-limiting embodimentswhen taken in conjunction with the accompanying drawings, in which:

FIG. 1 depicts a schematic representation of a mold-tool system (100);

FIGS. 2A and 2B depict other schematic representations of the mold-toolsystem (100) of FIG. 1; and

FIG. 3 depicts a schematic representation of a flow area (400) of themold-tool system (100) of FIG. 1.

The drawings are not necessarily to scale and may be illustrated byphantom lines, diagrammatic representations and fragmentary views. Incertain instances, details not necessary for an understanding of theembodiments (and/or details that render other details difficult toperceive) may have been omitted.

DETAILED DESCRIPTION OF THE NON-LIMITING EMBODIMENT(S)

FIG. 1 depicts the schematic representation of the mold-tool system(100). Specifically, FIG. 1 depicts a cross section of the mold-toolsystem (100). The mold-tool system (100) may include components that areknown to persons skilled in the art, and these known components will notbe described here; these known components are described, at least inpart, in the following reference books (for example): (i) “InjectionMolding Handbook” authored by OSSWALD/TURNG/GRAMANN (ISBN:3-446-21669-2), (ii) “Injection Molding Handbook” authored by ROSATO ANDROSATO (ISBN: 0-412-99381-3), (iii) “Injection Molding Systems” 3^(rd)Edition authored by JOHANNABER (ISBN 3-446-17733-7) and/or (iv) “Runnerand Gating Design Handbook” authored by BEAUMONT (ISBN 1-446-22672-9).It will be appreciated that for the purposes of this document, thephrase “includes (but is not limited to)” is equivalent to the word“comprising”. The word “comprising” is a transitional phrase or wordthat links the preamble of a patent claim to the specific elements setforth in the claim which define what the invention itself actually is.The transitional phrase acts as a limitation on the claim, indicatingwhether a similar device, method, or composition infringes the patent ifthe accused device (etc) contains more or fewer elements than the claimin the patent. The word “comprising” is to be treated as an opentransition, which is the broadest form of transition, as it does notlimit the preamble to whatever elements are identified in the claim.

The mold-tool system (100) includes (but is not limited to): asynergistic combination of a nozzle housing (102) and a valve stem(104). The nozzle housing (102) may be called a nozzle body. The nozzlehousing (102) has or defines a melt passageway (103) that extends froman input end (106) to an output end (108) along a longitudinal axis ofthe nozzle housing (102). The output end (108) is offset (or spacedapart) from the input end (106). The melt passageway (103) is used forconveying a melt (also known as a resin) from a runner assembly (knownbut not depicted) to a mold assembly (known but not depicted). The valvestem (104) is slide movable along the melt passageway (103). The valvestem (104) is slide supported at the input end (106) and at the outputend (108). “Slide supported” is defined such that when the valve stem(104) is slide reciprocated between open position and closed position, atip of the valve stem (104) is continuously slide supported (or guided)at the output end (108) so as to prevent the tip of the valve stem (104)from not being guided at the output end (108). It will be appreciatedthat the meaning of “the valve stem (104) is slide supported at theinput end (106)” covers either option of having the valve stem (104)being supported at the input end (106) and/or being supported at themanifold bushing (204). FIG. 1 depicts the valve stem (104) in the openposition so that the melt may flow through the nozzle housing (102) intothe mold assembly.

The nozzle housing (102) is received and held in position by a manifoldplate (202). The nozzle housing (102) abuts an end of a manifold bushing(204), The manifold bushing (204) is received in a manifold assembly(206). The manifold bushing (204) also defines a melt passageway (205)that fluidly connects with the melt passageway (103) of the nozzlehousing (102). The valve stem (104) slideably moves through the manifoldbushing (204). According to non-limiting variation, the output end (108)slide supports the valve stem (104) throughout an entire stroke of thevalve stem (104).

According to a non-limiting option, the mold-tool system (100) mayfurther include (but is not limited to) a nozzle tip (114). It will beappreciated that the nozzle tip (114) provides a structure for centeringthe valve stem (104) relative to the nozzle housing (102). The nozzletip (114) defines or includes a tip passageway (105) that is fluidlyconnected with the melt passageway (103) of the nozzle housing (102).The nozzle tip (114) is received in the output end (108) of the nozzlehousing (102). The nozzle tip (114) may be assembled to the nozzlehousing (102) with a tool, such as a wrench. The valve stem (104) isslidably supported by the nozzle tip (114). Generally, the nozzle tip(114) is connected with the nozzle housing (102). According to an optionthe nozzle tip (114) is connectably detachable to the nozzle housing(102) such as by way of a threaded connection. A vespel (208) may beused to cover a tip of the nozzle tip (114) at an exit portal (118) ofthe nozzle tip (114). The nozzle tip (114) also includes an entranceportal (120), and the melt passageway (103) extends from the entranceportal (120) to the exit portal (118). The entrance portal (120) ispositioned offset (or spaced apart) from the exit portal (118).According to an option, the nozzle tip (114) may have a flute structure(116) that is configured to allow a melt to flow around the valve stem(104) to the output end (108), and the flute structure (116) is used tosupport the valve stem (104) at the output end (108). The flutestructure (116) includes a flute defined at the exit portal (118) of thenozzle tip (114).

FIGS. 2A and 2B depict other schematic representations of the mold-toolsystem (100) of FIG. 1. FIG. 2A depicts an isometric view of the nozzletip (114). FIG. 2B depicts a cross-sectional view of the nozzle tip(114). The flute structure (116) defines a set of flutes that faces thevalve stem (104), and each flute is located evenly around the valve stem(104). The flute structure (116) is offset from the exit portal (118) ofthe nozzle tip (114). The flute structure (116) may include a flutewhich is formed in the exit portal (118).

FIG. 3 depicts a schematic representation of a flow area (400) of themold-tool system (100) of FIG. 1. The flute structure (116) ispositioned proximate to an exit portal (118) of the nozzle tip (114).The flute structure (116) is configured to allow plastic to flow aroundthe valve stem (104) that is placed in an open position. The valve stem(104) is movable between an open position and a closed position. In theclosed position, a tip of the valve stem (104) seals with a portion ofthe nozzle tip (114). In the opened position, the tip of the valve stem(104) does not seal with the portion of the nozzle tip (114) so that themelt may flow freely from the melt passageway (103) through the flutestructure (116) to the exit end of the nozzle housing (102).

The flute structure (116) forms a flow area (400) surrounding the valvestem (104) when the valve stem (104) is placed in the open position isequal to the flow area (300) defined by a cross sectional area of theexit portal (118) of the nozzle tip (114), so that the flow area (400)may be maintained while at the same time the valve stem (104) issupported.

Technical Advantages

Assuring that the valve stem (104) remains centered inside the meltpassageway (103) of the nozzle housing (102) and nozzle tip (114) mayresult in: (A) a better homogenized melt temperature and viscositydistribution around the valve stem (104), (B) a reduction in wearassociated with the nozzle tip (114), the valve stem (104) and a gateinsert (not depicted), (C) improved preform gate nub quality, (D)possible solution for gate tearing regardless of the type of valve stem(104) used (straight type, pressure-relief type, etc), (E) reduction inmelt flow lines with colorants and additives due to the shadow side of avalve stem (104), and/or (F) improvement of hot runner balancing.

Referring back to FIG. 1, the mold-tool system (100) is configured toaccommodate a valve stem (104). The mold-tool system (100) includes (andis not limited to): a nozzle assembly (402) that has a nozzle-output end(408). The nozzle-output end (408) is configured to support, at least inpart, slide movement of the valve stem (104). The following arecontemplated variations: the nozzle assembly (402) defines, at least inpart, a melt passageway (103) that is configured to accommodate slidemovement of the valve stem (104). The nozzle assembly (402) has anozzle-input end (406) that is configured to support, at least in part,slide movement of the valve stem (104). The nozzle-input end (406) isconfigured to interface with a manifold bushing (204). The manifoldbushing (204) is configured to support, at least in part, slide movementoft the valve stem (104). The nozzle assembly (402) has a meltpassageway (103) that extends from the nozzle-input end (406) to thenozzle-output end (408). The nozzle-output end (408) is set apart fromthe nozzle-input end (406). The nozzle-output end (408) includes (and isnot limited to): a flute structure (116) that is configured to support,at least in part, slide movement of the valve stem (104). Optionally,the nozzle assembly (402) includes (and is not limited to) a nozzle tip(114) that is configured to be received in the nozzle-output end (408).The nozzle tip (114) has the flute structure (116) that is configured tosupport, at least in part, slide movement of the valve stem (104). Theflute structure (116) is configured to allow a melt to flow around thevalve stem (104) to the nozzle-output end (408). The valve stem (104) isslidably supported by the nozzle tip (114) at the flute structure (116).The output end (408) slide supports the valve stem (104) throughout anentire stroke of the valve stem (104). The nozzle tip (114) is receivedin the output end (408) of the nozzle assembly (402). The valve stem(104) is slidably supported by the nozzle tip (114). The flute structure(116) is configured to allow a melt to flow around the valve stem (104)to the output end (108). The valve stem (104) is slidably supported bythe nozzle tip (114) at the flute structure (116). The flute structure(116) is positioned proximate to an exit portal (118) of the nozzle tip(114). The flute structure (116) is configured to allow plastic to flowaround the valve stem (104) that is placed in an open position. Theflute structure (116) forms a flow area (400) surrounding the valve stem(104) when the valve stem (104) is placed in the open position is equalto the flow area defined by a cross sectional area of the exit portal(118) of the nozzle tip (114), so that the flow area may be maintainedwhile at the same time the valve stem (104) is supported.

Additional Description

The following clauses are offered as further description of the aspectsof the embodiments of the present invention:

Clause (1). A mold-tool system (100), comprising: a nozzle housing (102)having a melt passageway (103) extending from an input end (106) to anoutput end (108) being offset from the input end (106); and a valve stem(104) being: (i) slide movable along the melt passageway (103), and (ii)slide supported by the input end (106) and by the output end (108).Clause (2). The mold-tool system (100) of clause (1), wherein: theoutput end (108) slide supports the valve stem (104) throughout anentire stroke of the valve stem (104). Clause (3). The mold-tool system(100) of any preceding clause, further comprising: a nozzle tip (114)being received in the output end (108) of the nozzle housing (102), andthe valve stem (104) is slidably supported by the nozzle tip (114).Clause (4). The mold-tool system (100) of any preceding clause, furthercomprising: a nozzle tip (114) being received in the output end (108) ofthe nozzle housing (102), the nozzle tip (114) having: a flute structure(116) being configured to allow a melt to flow around the valve stem(104) to the output end (108), and the valve stem (104) is slidablysupported by the nozzle tip (114) at the flute structure (116). Clause(5). The mold-tool system (100) of any preceding clause, wherein: theflute structure (116) is positioned proximate to an exit portal (118) ofthe nozzle tip (114), the flute structure (116) is configured to allowplastic to flow around the valve stem (104) that is placed in an openposition. Clause (6). The mold-tool system (100) of any precedingclause, wherein: the flute structure (116) forms a flow area (400)surrounding the valve stem (104) when the valve stem (104) is placed inthe open position is equal to the flow area (300) defined by a crosssectional area of the exit portal (118) of the nozzle tip (114), so thatthe flow area (400) may be maintained while at the same time the valvestem (104) is supported. Clause (7). A molding system having themold-tool system (100) of any of any preceding clause.

It is understood that the scope of the present invention is limited tothe scope provided by the independent claims, and it is also understoodthat the scope of the present invention is not limited to: (i) thedependent claims, (ii) the detailed description of the non-limitingembodiments, (iii) the summary, (iv) the abstract, and/or (v)description provided outside of this document (that is, outside of theinstant application as filed, as prosecuted, and/or as granted). It isunderstood, for the purposes of this document, the phrase “includes (butis not limited to)” is equivalent to the word “comprising”. The word“comprising” is a transitional phrase or word that links the preamble ofa patent claim to the specific elements set forth in the claim whichdefine what the invention itself actually is. The transitional phraseacts as a limitation on the claim, indicating whether a similar device,method, or composition infringes the patent if the accused device (etc)contains more or fewer elements than the claim in the patent. The word“comprising” is to be treated as an open transition, which is thebroadest form of transition, as it does not limit the preamble towhatever elements are identified in the claim. It is noted that theforegoing has outlined the non-limiting embodiments. Thus, although thedescription is made for particular non-limiting embodiments, the scopeof the present invention is suitable and applicable to otherarrangements and applications. Modifications to the non-limitingembodiments can be effected without departing from the scope of theindependent claims. It is understood that the non-limiting embodimentsare merely illustrative.

What is claimed is:
 1. A mold-tool system (100) configured to accommodate a valve stem (104), the mold-tool system (100) comprising: a nozzle assembly (402) having: a nozzle-output end (408) being configured to support, at least in part, slide movement of the valve stem (104), and a nozzle tip (114) being received in the nozzle-output end (408), the nozzle tip (114) including: a flute structure (116) positioned proximate to an exit portal (118) of the nozzle tip (114), the flute structure (116) configured to slidably support the valve stem (104) while at the same time maintaining a flow area (400) surrounding the valve stem (104) along the entire length that the valve stem (104) is slidably supported by the flute structure (116) when the valve stem (104) is placed in the open position, the flow area (400) being equal to the flow area (300) defined by a cross sectional area of the exit portal (118) of the nozzle tip (114).
 2. The mold-tool system (100) of claim 1, wherein: the nozzle assembly (402) defines, at least in part, a melt passageway (103) being configured to accommodate slide movement of the valve stem (104).
 3. The mold-tool system (100) of claim 1, wherein: the nozzle assembly (402) has a nozzle-input end (406) being configured to support, at least in part, slide movement of the valve stem (104).
 4. The mold-tool system (100) of claim 1, wherein: the nozzle assembly (402) has a nozzle-input end (406) being configured to interface with a manifold bushing (204), the manifold bushing (204) being configured to support, at least in part, slide movement of the valve stem (104).
 5. The mold-tool system (100) of claim 1, wherein: the nozzle assembly (402) has a melt passageway (103) extending from an nozzle-input end (406) to the nozzle-output end (408) being set apart from the nozzle-input end (406).
 6. The mold-tool system (100) of claim 1, wherein: the output end (408) slide supports the valve stem (104) throughout an entire stroke of the valve stem (104).
 7. A molding system having the mold-tool system (100) of any one of claims 1-5 and
 6. 